From Wikipedia:
QUOTE
Executor is unable to run Macintosh programs designed to run on PowerPC-based Macintosh hardware. Executor can mimic either Macintosh System 7.0.0 or System 6.0.7 for older applications that don't work in System 7.0.0 mode.
Use a different emulator for Windows like SheepShaver or Basilisk II and try it. This is just a hunch, but StuffIt Expander for Windows might be able to extract your mac files properly.